Method of making a semiconductor device
AssigneeFujitsu Limited
InventorsMikio Takagi, Hajime Kamioka, Kazufumi Nakayama, Haruo Shimoda
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Abstract
A method of making a semiconductor device capable of high-speed operation is disclosed in which when the current gain-bandwidth is increased by the formation of a shallow base region. A side etching process is used to decrease the base spreading resistance and to allow ease in the formation of an emitter region of fine pattern. When the emitter region is formed by using polycrystalline silicon as a source of impurity diffusion, that area of an insulating film on a semiconductor substrate which adjoins the polycrystalline silicon is removed before the impurity diffusion so as to prevent an abnormal diffusion phenomenon. BACKGROUND OF THE INVENTION
Claims19
A method of making a semiconductor device comprising the steps of forming an insulating film on a semiconductor substrate;
- selectively removing said insulating film to form therein a window to expose the surface of said semiconductor substrate therethrough;
- forming in said window a semiconductor layer containing an impurity for diffusion, said semiconductor layer being small in area enough not to make contact with said insulating film;
- and diffusing the impurity by heat treatment from said semiconductor layer into said semiconductor substrate.
A method of making a semiconductor device comprising the steps of sequentially forming on a semiconductor substrate a first insulating layer, a second layer of a material different from that of said first insulating layer and a third insulating layer of the same material as that of said first insulating layer;
- patterning said first insulating layer, said second layer and said third insulating layer in a desired pattern;
- effecting side etching of said second layer;
- patterning said first insulating layer using said second layer as a mask;
- forming a layer of a material different from that of said first insulating layer to surround said first insulating layer;
- and selectively removing said first insulating layer to form a window to expose said semiconductor substrate therethrough.
Dependencies are inferred from the claim text.